<template>
    <div class="todo-footer" v-show="total">
			  <label>
				<!-- <input type="checkbox" :checked="isAll" @change="checkAll"/> -->
                <input type="checkbox" v-model="isAll"/>
			  </label>
			  <span>
				<span>已完成{{ doneTotal}}</span> / 全部{{total}}
			  </span>
			  <button class="btn btn-danger" @click="clearAll">清除已完成任务</button>
	</div>
</template>

<script>
    export default {
        name:'my-footer',
        props:['todos','checkAllTodo','clearAllTodo'],
        computed:{
            total(){
                return this.todos.length
            },
            doneTotal(){
                // let i=0
                // this.todos.forEach((todo) => {
                //     if(todo.done) i++
                // });
                // return i

                //reduce是条件统计
                //pre上一次调用reduce返回的值，current现在的对象
                //0表示初始值
                // return this.todos.reduce((pre,current)=>{
                //     return pre + (current.done?1:0)
                // },0)
                return this.todos.reduce((pre,current)=> pre + (current.done?1:0),0)
            },
            // isAll(){
            //     return this.doneTotal===this.total && this.total>0
            // }
            isAll:{
                get(){
                    return this.doneTotal===this.total && this.total>0
                },
                set(value){
                    this.checkAllTodo(value)
                }
            }
        },
        // methods:{
        //     checkAll(e){
        //         this.checkAllTodo(e.target.checked)
        //     }
        // }
        methods:{
            clearAll(){
                this.clearAllTodo()
            }
        }
    }
</script>

<style scoped>
    /*footer*/
	.todo-footer {
		height: 40px;
		line-height: 40px;
		padding-left: 6px;
		margin-top: 5px;
	}
	
	.todo-footer label {
		display: inline-block;
		margin-right: 20px;
		cursor: pointer;
	}
	
	.todo-footer label input {
		position: relative;
		top: -1px;
		vertical-align: middle;
		margin-right: 5px;
	}
	
	.todo-footer button {
		float: right;
		margin-top: 5px;
	}
</style>